Vertical paper machine

ABSTRACT

IN A TWO-WIRE VERTICAL PAPER MACHINE, THE OPPOSED DOWNWARDLY TRAVELING REACHES OF THE TWO WIRES WHICH CONVERGE TO DEFINE THE FORMING ZONE ARE LED PARTIALLY AROUND A SINGLE COUCH ROLL LOCATED BELOW THE FORMING ZONE, THE UPPER RUN OF THE RESULTING SUPERIMPOSED WIRES IS THEN CAUSED TO DIVERGE FROM THE LOWER WIRE, AND THE SHEET IS CARRIED ON THE RESULTING GENERALLY HORIZONTALLY TRAVELING WIRE RUN TO A PICKUP STATION. THIS CONSTRUCTION OF VERTICAL PAPER MACHINE IS ESPECIALLY ADAPTED FOR USE WITH A CONVENTIONAL PICKUP ROLL AND FELT ARRANGED TO PICK UP THE SHEET FROM THE UPPER SURFACE OF THE WIRE RUN.

March 30, 1971 w. c. NOTBOHM VERTICAL PAPER momma Filed Oct. 17, 1968 Mil/EN TOR WILLARD C. NOTBOHM BY Z 42, Z

ATTORNEYS United States Patent 3,573,161 VERTICAL PAPER MACHINE Willard C. Notbohm, Water-town, N.Y., assignor to The Black Clawson Company, Hamilton, Ohio Filed Oct. 17, 1968, Ser. No. 768,284 lint. Cl. D21f 2/00 US. Cl. 162301 7 Claims ABSTRACT OF THE DISCLOSURE In a two-wire vertical paper machine, the opposed downwardly traveling reaches of the two wires which converge to define the forming zone are led partially around a single couch roll located below the forming zone, the upper run of the resulting superimposed wires is then caused to diverge from the lower wire, and the sheet is carried on the resulting generally horizontally traveling wire run to a pickup station. This construction of vertical paper machine is especially adapted for use with a conventional pickup roll and felt arranged to pick up the sheet from the upper surface of the wire run.

REFERENCE TO COPENDING APPLICATIONS Ser. No. 703,299, filed Feb. 6, 1968, Notbohm et al.; Ser. No. 706,514, filed Feb. 19, 1968, McCarrick et al.; Ser. No. 711,583, filed Mar. 8, 1968, McCarrick et al.; Ser. No. 755,602, Aug. 27, 1968, Notbohm et a1.

BACKGROUND OF THE INVENTION This invention relates to paper making machines generally of the type shown in Baxter Patent No. Re. 25,333, and characterized by the incorporation of a pair of end less forming wires arranged to wrap a corresponding pair of horizontally spaced breast rolls in such manner as to provide a pair of opposed reaches which travel downwardly from the breast rolls in closely spaced converging relation to create the zone wherein the paper sheet is formed. The invention also relates to the similar vertical paper machines shown in Baxter et a1. Patent No. 3,215,- 594 and characterized by the provision of multiple defiectors which support the traveling wires in the desired converging relation wherein they define the forming zone. The above copending applications relate to improvements in vertical paper machines generally of the type shown in the Baxter and Baxter et al. patents which may be incorporated in a vertical paper machine in accordance with the present invention.

Vertical paper machines of the type to which the present invention relates offer a variety of important advantages over conventional Fourdrinier paper machines, including economy of both initial construction and maintenance, and especially the production of paper of better quality from the standpoint of both squareness and uniform surface characteristics on both sides of the sheet. Another outstanding advantage lies in the ease with which a vertical forming section can be installed in place of an existing Fourdrinier section and adapted to operate in combination with the press and other sections of the existing machine as part of a rebuilding program on an old machine.

It is not always possible to use the same design of vertical section for rebuilding any existing machine, particularly if the existing pickup arrangement and first press section are to be retained. The present invention is directed to this problem, and especially to the provision of a vertical forming section of such construction and arrangement that one of the forming wires retains the sheet thereon until it presents the sheet on an upper run thereof to a pickup roll and felt located above the sheet.

SUMMARY OF THE INVENTION A vertical forming section in accordance with the present invention is preferably constructed to operate as described in Notbohm et al. Ser.. No. 755,602 in such manner that the sheet is formed in a forming zone defined by two converging wires moving generally vertically along essentially straight lines and guided by water-doctoring deflectors to a level where they are held apart only by the resistance to their tension provided by the fibrous mat or sheet which has been formed therebetween by felting and compaction of the fibers remaining from the progressive dewatering through the wires. Then after formation of the sheet has thus been completed, the two wires, with the sheet therebetween, partially wrap a common couch roll and move toward a turning roll spaced laterally from the central plane of the forming zone.

The two wires leave the couch roll in superimposed relation with the sheet still therebetween, and a guide roll for the upper wire is positioned to cause it to diverge from the other wire as the latter passes across a suction box effective to hold the sheet thereon. The resulting sin gle wire run, with the sheet on its upper side, proceeds towards its turning and drive roll, which is so located with respect to the pickup roll of the paper machine that the sheet can be picked up from the wire before the wire wraps the turning roll for return to the forming zone.

It is the primary object of the present invention to provide a vertical paper machine which will have the advantages of the vertical paper machines shown in the above patents and applications from the standpoint of structure and operation as Well as from the standpoint of quality of product, and which also will operate properly in combination with a sheet pickup arranged to pick the sheet up from the upper surface of a generally horizontal wire run. Additional objects and advantages will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWING The single view is a side elevation illustrating diagrammatically one form of vertical paper machine and sheet pickup arrangement constructed in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing shows the general construction of a vertical paper machine including a pair of breast rolls 10 and 11 supported in horizontally spaced relation on frames 12 and 13. A single couch roll 15 is mounted on the frame 13 below and generally in line with the righthand breast roll 11, and a pair of forming wires 16 and 17 are looped around the respective breast rolls 10 and 11 and are brought together partially around the couch roll 15, the terms wires being used generically as including foraminous forming webs of any suitable mate rial. The remainder of the loop of the righthand wire 17 is supported by a fixed guide roll .20, an adjustable guide roll 22, and tensioning rolls 23. The lefthand wire 16 is supported by a turning roll 25, an adjustable guide roll 26 and tensioning rolls 27. The couch roll 15 and turning roll 25 are provided with adjustable drive means (not shown) to cause the wires to travel downwardly from the breast rolls 10-11 in desire-d speed relation, which is preferably essentially synchronous.

The reaches of the wires 16 and 17 directly below the breast rolls 1t and 11 are guided so that they converge to define therebetween a forming zone 30 of generally triangular section open at its larger end to the gap 31 between the breast rolls to receive stock from the headbox 33, which is represented diagrammatically and is preferably of the construction shown in the above Notbohm et al. application Ser. No. 703,299. The wire reaches defining the forming zone are guided by deflectors 35 which engage the inner surfaces of these wire reaches in supporting relation, and which also serve to skim off water expressed through the wires and to guide this water into save-all pans (not shown) within the frames 12 and 13 for removal to a collection station remote from the machine. These deflectors 35 are advantageously of the adjustable construction shown in the above application Ser. No. 706,514. An additional deflector 37 is provided along the upper edge of a suction box 40 mounted on the frame below the lowermost of the deflectors 35.

The spacing and arrangements of the deflectors 35 with respect to each other and to the gap 31 above the forming zone are determined in accordance with the principles described in Notbohm application Ser. No. 755,602 so that the stock is delivered as a sheet-like jet to the upper end of the forming zone by the headbox 33 so that it impinges on the wires 16-17 below the level at which the pumping action of the breast rolls 10-11 would tend to draw liquid through the wires, i.e. substantially below the line of tangency of each wire with its associated breast roll. The stock is progressively dewatered as it travels downwardly with the forming wires until at the level of the deflector 37, the major volume of free water has been expressed through the wires, and the fibers remaining between the wires have been compacted and felted into a mat or sheet which provides the only force holding the wires apart against their tension. Stated differently, the number and spacing of the deflectors are such that at the level of the deflector 37, the forming wires cease to be urged toward each other by any force other than their tension, and with the stock dewatered to this extent, formation of the sheet is sufliciently complete that if an additional deflector Were used, it would not cause a significant amount of water to be expressed through the wires.

The suction box 40 is accordingly located beyond the level at which formation of the sheet is complete in order to withdraw additional water by suction action. After the two wires with the sheet therebetween pass the suction box 40, they partially wrap the couch roll and proceed laterally toward the turning roll 25. Just beyond the couch roll 15, there is located a second fixed suction box 42 over which the two wires pass, but the guide roll for the righthand wire 17 is so located beyond the suction box 42 as to cause wire 17 to diverge from wire 16 as the two wires pass across the suction box 42. The action of the suction box 42 will therefore hold the sheet on the generally horizontal run of wire 16 while wire 17 diverges therefrom around its guide roll 20.

The sheet travels beyond suction box 42 on the upper surface of the horizontal run of wire 16 toward the turning roll 25, and a suction roll 44 may be located between suction box 42 and roll to remove additional water from the sheet if desired. A suction pickup roll 45 and cooperating felt 46 are located to pick the sheet up from wire 16 before it wraps roll 25, and preferably before it reaches roll 25. The roll 45 may also serve as one roll of the first press section, as indicated by that dotted roll 48, or the felt 46 may transport the sheet to a separate first press section.

The invention thus retains the significant advantages of the vertical forming machines shown in the above patents and applications because, in operation, formation of the paper sheet is effectively completed while the wires are traveling along essentially straight paths defining a forming zone which is similarly essentially straight. It also provides for the removal of additional Water from the sheet before it separates from the carrier wire 16, through the use of the two suction boxes 40 and 42 and the suction roll 44, while still presenting the sheet on the upper surface of a generally horizon al wire run for easy pickup and transfer to the first press section of the paper machine. In fact, it is possible with the invention to use both the pickup arrangement of an existing machine and also the wire drive roll of the existing machine, which is readily useable as the turning and drive roll 25 for the wire 16.

The drawing also illustrates the ease with which the wires can be changed on a machine in accordance with the invention. The two frames 12 and 13 at the front side of the machine are indicated as each supported from the back of the machine by a cantilever beam 50 and 51 respectively, and the pedestals at the front of the machine incorporate removable blocks 5254 which are removed for wire changing. In addition, one section 55 of the pedestal for the frame 13 is supported by its own cantilever beam 56. The rolls 25 and 44 may be provided in conventional fashion with cantilever extensions at the back of the machine, as well as with a removable block at the front side of the machine as indicated at 59 between the bearing housing 58 for the roll 25 and its pedestal 60. For wire changing, therefore, nothing more is required to free the front end than removal of the several removable blocks, after which the wires can be quickly and easily removed and replaced.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. Apparatus for forming a paper sheet between a pair or looped forming Wires and including a pair of breast rolls cooperating to support a pair of downwardly traveling reaches of said wires in opposed relation defining a forming zone, comprising means supporting said breast rolls in such spaced relation that horizontally opposed upper portions of said wire reaches define a mouth for said forming zone, headbox means for supplying paper making stock to said mouth from above, guide means positioned to guide said reaches in converging relation from said mouth to cause said wires to exert pressure on stock within said forming zone forcing the liquid therein to be extruded through said wires while the fibers remaining therein form a paper sheet, a couch roll located generally below said breast rolls and positioned to receive both of said wires therearound with one said 'wire engaging said couch roll and with the sheet between said one wire and the second said wire, a turning roll receiving said second wire therearound and spaced a suflicient distance laterally from said couch roll to cause said second wire to travel laterally thereto from said couch roll with the sheet on the upper surface thereof, a guide roll for said one Wire positioned to cause said one wire to diverge from said second wire between said couch and turning rolls, and transfer means cooperating with said second wire to remove the sheet therefrom for delivery to a further processing station.

2. Apparatus as defined in claim 1 wherein said guide means include a plurality of deflectors engaging the surfaces of said wires outside said forming zone to remove the extruded liquid therefrom, and comprising means supporting said deflectors in vertically spaced planes, each deflector which engages one of said wires being positioned opposite a space adjacent the nearest said deflector which engages the other said wire.

3. Apparatus as defined in claim 1 comprising a suction box located above said couch roll and in engagement with said second wire for removing water from the sheet between said wires.

4. Apparatus as defined in claim 1 comprising a suction box positioned in engagement with the underside of said second wire at the location between said couch roll and said turning roll at which said first :wire begins to diverge from said second wire for holding the sheet on said second wire.

5. Apparatus as defined in claim 1 comprising a suction box located above said couch roll and in engagement with said second wire for removing water from the sheet between said wires, and an additional suction box positioned in engagement with the underside of said second wire at the location between said couch roll and said turning roll at which said first wire begins to diverge from said second wire for holding the sheet on said second wire.

6. Apparatus as defined in claim 2 comprising a suction box located above said couch roll and in engagement with said second wire for removing water from the sheet between said wires, and an additional suction box positioned in engagement with the underside of said second wire at the location between said couch roll and said turning roll at which said first wire begins to diverge from said second wire for holding the sheet on said second wire.

7. Apparatus as defined in any one of claims 1 to 6 comprising means supporting said breast rolls in such horizontally spaced relation that the horizontally opposed upper portions of said wire reaches define a mouth of predetermined width for said forming zone, and said headbox means including means for discharging a jet of stock of predetermined cross sectional dimensions similar in thickness to said width of said mouth and for so directing said jet into said mouth that said jet impinges on each of said wires at a location spaced substantially below the line of tangency of said wire with its associated said breast roll.

References Cited UNITED STATES PATENTS 7/1966 Embry 162203 6/1967 Graham 162348 US. Cl. X.R. 162--20*3 

